Is my 5.7 4-bolt main?

[Crazydavez28]

To answer the question this was not 4 bolt main. It might not be a fair comparison bc I yanked the motor and upon tearing it down all the gasket were very recent, not original, and #4 rod was so jacked the piston was smacking the head. I don't think this was the original motor. hard to imagine as the tahoe only shows 106k miles but i guess the intake gaskets caused a few premature deaths.

I'm building a bone stock replacement that i hope to drop in this weekend. I think since the crank and rods are junk and the bores are worn. Im contemplating building a long rod L31 or possibly a long rod 327 out of the block.

 

[L31MaxExpress]

To answer the question this was not 4 bolt main. It might not be a fair comparison bc I yanked the motor and upon tearing it down all the gasket were very recent, not original, and #4 rod was so jacked the piston was smacking the head. I don't think this was the original motor. hard to imagine as the tahoe only shows 106k miles but i guess the intake gaskets caused a few premature deaths.

I'm building a bone stock replacement that i hope to drop in this weekend. I think since the crank and rods are junk and the bores are worn. Im contemplating building a long rod L31 or possibly a long rod 327 out of the block.

The engine my Express van came from GM with died in 2004 with 57K on the odometer. Hydrolocked on startup because of a bad intake gasket that allowed coolant to enter and fill the #2 intake port, that when the engine was turned over to start, shattered #2 connecting rod. Had no prior symptoms of the intake gaskets leaking, was parked for about 2 weeks, went to start it and BOOM, clank, clank, clank! Later tear down found that intake port and cylinder filled with coolant and the intake gaskets failed.

I would build a 6" rod 383 in your situation. No sense to not get as many cubes as you can. Alternatively I would also have a hard time not spending a little more money and building a 396 aka 3.875" stroke, 6" rod with a 4.030" bore. There are numerous 396 LT1 Impala SS cars floating around and they make monster torque compared to a stock cube 350.

 

[Gibson]

You might want to consider what kind of use you want the engine for.
The "long rod" engines are more suitable for use with aggressive cams with the torque coming on at higher revs,, as they offer more "dwell time", measured as degrees, at the ends of the stroke, this gives a bigger "window" of time for aggressive valve action.
For an everyday small block 350, that needs it torque in the 2800>~3400 rpm, you're better off with the stock 5.7 rods.

 

[L31MaxExpress]

You might want to consider what kind of use you want the engine for.
The "long rod" engines are more suitable for use with aggressive cams with the torque coming on at higher revs,, as they offer more "dwell time", measured as degrees, at the ends of the stroke, this gives a bigger "window" of time for aggressive valve action.
For an everyday small block 350, that needs it torque in the 2800>~3400 rpm, you're better off with the stock 5.7 rods.

It has been proven in many comparisons long rods have very little effect on power curve and are more useful in controlling piston side loading and thus friction, promoting longer bore life from less side load.

 

[Gibson]

It has been proven in many comparisons long rods have very little effect on power curve and are more useful in controlling piston side loading and thus friction, promoting longer bore life from less side load.

Yes, what you said is technically true, if the engine is "stock".
So, you can spend more money getting longer rods and special pistons that have the piston pin raised up, which will decrease the side loading a small percentage,, is that worth it on a stock engine, only the person who's paying for the parts can answer that.
Still, the main advantage of long rods, is to be able to take advantage of long duration cams.
With a longer rod, the period of time in which the piston is moving slowly is greater in crankshaft degrees, and that allows more time for a big cam to do its job, and cylinder filling to take place.
When you're going for big hp at higher rpms using an aggressive cam, long rods can help the engine in its breathing,, but for a stocker you spend a lot for just a little less side load.

 

[L31MaxExpress]

Yes, what you said is technically true, if the engine is "stock".
So, you can spend more money getting longer rods and special pistons that have the piston pin raised up, which will decrease the side loading ~1 1/2 percent,, is that worth it on a stock engine, only the person who's paying for the parts can answer that.
Still, the main advantage of long rods, is to be able to take advantage of long duration cams.
With a longer rod, the period of time in which the piston is moving slowly is greater in crankshaft degrees, and that allows more time for a big cam to do its job, and cylinder filling to take place.
When you're going for big hp at higher rpms using an aggressive cam, long rods can help the engine in its breathing,, but for a stocker you spend a lot for just a little less side load.

When I suggested a 6" rod it was for a stroked engine not a stock 350. Aftermarket rotating assemblies with 6" rods make more sense to me than trying to recondition the stock GM junk in this day and age.

While it is possible to build a 383 or even a 396 with a 5.7" rod or even a 5.565" rod, it would make for the same poor Rod/Stroke ratio that a factory 400 small block came with.

The OEM trend now is longer rods. Manufacturers have even increased deck heights on some versions of engines with higher outputs to put a longer rod in them.

 

[Gibson]

When I suggested a 6" rod it was for a stroked engine not a stock 350. Aftermarket rotating assemblies with 6" rods make more sense to me than trying to recondition the stock GM junk in this day and age.

While it is possible to build a 383 or even a 396 with a 5.7" rod or even a 5.565" rod, it would make for the same poor Rod/Stroke ratio that a factory 400 small block came with.

The OEM trend now is longer rods. Manufacturers have even increased deck heights on some versions of engines with higher outputs to put a longer rod in them.

Yeah, you're right. If I was building a stroker I'd want the longer rods for sure,, and it's interesting that when GM replaced the 454 with the 496, (8.1,) they went with a taller deck,, even back in the older days the old 366 truck engine had a taller deck height,, a lot of people don't like that engine but it is a great engine for low rpm torque, like for using to tow with.

 

[L31MaxExpress]

Yeah, you're right. If I was building a stroker I'd want the longer rods for sure,, and it's interesting that when GM replaced the 454 with the 496, (8.1,) they went with a taller deck,, even back in the older days the old 366 truck engine had a taller deck height,, a lot of people don't like that engine but it is a great engine for low rpm torque, like for using to tow with.

Those big trucks had a nice tall deck 427 as an option as well! Tall deck truck 427 makes even more torque for towing than a 366. The 366 is a very rugged engine but its 283 like bore and heavy big block parts make it somewhat of a boat anchor as far as performance is concerned. Alot like the 260 ci small blocks from all the manufacturers in the 70s and 80s their bores are just too small to get decent heads on.

 

[Crazydavez28]

I have been trying to read up on the rod/stroke ratio and compression ratios. I believe with the long rod you have more dwell during combustion allowing more torque to be generated. I did read that the long rod has less tendency to knock as well.

The strokers are tempting but finding clearance for every thing can cost a guy. I already have to find a crank, rods, and pistons. Got a Comp 08-416-8 cam on the shelf that should go real nice in a long rod 355.

Anybody have good results with the 305 vortec heads? (i'm getting at the small runners, chambers, and un-shrouded valves on the 4.030 bore). Do they play well with a stock intake?

 

[Schurkey]

The whole reason for the tall deck on the 366 and 427 was to accommodate a taller piston having four rings instead of three. The piston was .400 taller, so the deck was .400 taller.

They wanted an extra ring to control oil on the cylinder wall. Those engines ran at or near WFO the whole time they were loaded and on the highway between the field and the elevator--or between the last garbage dumpster and the landfill. They would be so heavily-loaded the exhaust manifolds would glow orange.

The 366 pretty-much couldn't make enough power to hurt itself. The 427 could.